usb: gadget: legacy: fix error return code of msg_bind()

When usb_otg_descriptor_alloc() returns NULL to usb_desc, no error
return code of msg_bind() is assigned.
To fix this bug, status is assigned with -ENOMEM in this case.

Reported-by: TOTE Robot <oslab@tsinghua.edu.cn>
Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
Link: https://lore.kernel.org/r/20210323123648.3997-1-baijiaju1990@gmail.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>